Accumulator

ABSTRACT

In an accumulator for use in a refrigerating cycle of a vehicle air conditioner or the like, to prevent a refrigerant liquid sucked inside returning to a compressor. 
     A desiccant layer  12  is provided above the middle of a tank  11  to divide the main body into upper and lower chambers  13  and  14.  A gas-liquid mixed refrigerant sucked into the lower chamber is subjected to gas-liquid separation in the desiccant layer  12,  and only the refrigerant gas is transferred to the upper chamber  13  while the refrigerant liquid and the like are accumulated in the lower chamber  14.  An outlet port  16   b  of the refrigerant suction tube  16,  through which the refrigerant is sucked into the main body, is opened within the lower chamber  14,  and an inlet port  17   a  of a refrigerant/oil discharge tube  17,  through which refrigerant gas obtained by the gas-liquid separation in the desiccant layer  12  is discharged, is opened within the upper chamber  13.  The desiccant layer  12  separates the outlet port  16   b  of the refrigerant suction tube  16  from the inlet port  17   a  of the refrigerant/oil discharge tube  17,  so that the refrigerant liquid sucked through the refrigerant suction tube  16  is not directly sucked into the inlet port  17   a  of the refrigerant/oil tube  17.

TECHNICAL FIELD

The present invention relates to a structure of an accumulator for usein a refrigerating cycle of a vehicle air-conditioner or the like.

BACKGROUND ART

Heretofore, in a refrigerating cycle of a vehicle air-conditioner, anaccumulator is disposed on a side of a compressor to which a refrigerantreturns. Herein, the compressor compresses the refrigerant. In a coolingdedicated cycle of a general vehicle including an engine as a drivingsource, such an accumulator is an essential part to store redundantrefrigerant due to variations in load during the cooling operation. In aheating and cooling cycle of a vehicle which does not include a heatsource such as a fuel cell vehicle or an electrical vehicle, in additionto such a function of storing redundant refrigerant, the accumulator hasa function of separating the refrigerant returning to the compressorinto liquid and gas and allowing only refrigerant gas to be sucked intothe compressor, thus preventing damage of the compressor due to liquidor wet compression.

FIG. 3 is a schematic cross-sectional view showing a conventionalexample of a general accumulator. This accumulator 100 is connected to apath reaching a compressor from a not-shown internal heat exchanger andincludes a refrigerant suction tube 102 and a substantially U-shapedrefrigerant discharge tube 103 within a substantially cylindrical tank101. The refrigerant suction tube 102 is connected to an inletrefrigerant pipe which is connected to the not-shown internal heatexchanger, and a gas-liquid mixed refrigerant is flown through therefrigerant suction tube 102 into the tank 101. The refrigerantdischarge tube 103 is connected to an outlet refrigerant pipe which isconnected to the not-shown compressor and discharges the refrigerant gasobtained by gas-liquid separation. In a tank upper part of therefrigerant discharge tube 103, a refrigerant return opening 103 athrough which the refrigerant gas is sucked is formed, and, in a bentpart of the substantially U shape thereof, an oil return port 103 b isformed, through which oil contained in a refrigerant liquid is returned.

In the aforementioned structure, the gas-liquid mixed refrigerantdischarged from the not-shown internal heat exchanger is flown throughthe refrigerant suction tube 102 into the tank 101, and the refrigerantliquid is accumulated in the bottom of the tank 101. The refrigerant gasis sucked through the refrigerant return opening 103 a of therefrigerant discharge tube 103 and fed to the not-shown compressorthrough the refrigerant discharge tube 103. The oil contained in therefrigerant liquid accumulated in the bottom of the tank 101 is suckedthrough the oil return port 103 b formed in the refrigerant dischargetube 103 and fed to the compressor together with the refrigerant gas.

As a conventional art related to this type of accumulator, anaccumulator is proposed in which the tank is partitioned by a desiccantunit into upper and lower chambers. The upper chamber is divided by aseparator wall into a chamber on the refrigerant inlet side and achamber on the refrigerant outlet side, and the separator wall includesa number of ventilation holes (see Patent Literature 1).

Patent Literature 1: Japanese Patent Laid-open Publication No. 10-232071

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In the accumulator 100 of the conventional example shown in FIG. 3, thegas-liquid mixed refrigerant sucked through the refrigerant suction tube102 sometimes enters the refrigerant discharge tube 103 through therefrigerant return opening 103 a as indicated by a solid arrow.Moreover, the gas-liquid mixed refrigerant flown into the tank strikesthe surface of the accumulated liquid and ruffles the surface thereof,and accordingly, the refrigerant liquid in the surface sometimes reachesthe refrigerant return opening 103 a and enters the refrigerantdischarge tube 103. In the accumulator 100 of the conventional exampleshown in FIG. 3, the refrigerant liquid is sent to the compressor insuch a manner, and the compressor could be damaged by liquid or wetcompression.

In the accumulator proposed by Japanese Patent Laid-open Publication No.10-232071, the refrigerant liquid flown into the chamber on therefrigerant inlet side passes through the desiccant unit and isaccumulated in a lower chamber, and the refrigerant liquid does notruffle the surface of the accumulated liquid. However, a lot ofventilation holes are formed in the separator wall separating thechambers on the refrigerant inlet and outlet sides, and it is thoughtthat a part of the refrigerant liquid flown into the chamber on therefrigerant inlet side could enter the opposite chamber on therefrigerant outlet side through these ventilation holes and sent to thecompressor. Accordingly, in such an accumulator, the refrigerant liquidreturning to the compressor is not prevented.

An object of the present invention is to provide an accumulator capableof preventing the refrigerant liquid sucked inside returning to thecompressor.

Means for Solving the Problems

To achieve the aforementioned object, an accumulator according to thepresent invention includes: a main body; and a desiccant layer which isprovided above a middle of the main body to divide the main body intoupper and lower chambers. A gas-liquid mixed refrigerant sucked into thelower chamber is subjected to gas-liquid separation in the desiccantlayer, and only the refrigerant gas is transferred to the upper chamber.Moreover, an outlet port of a refrigerant suction tube through which therefrigerant is sucked into the body is opened within the lower chamber,and an inlet port of a refrigerant discharge tube through which therefrigerant gas obtained by the gas-liquid separation in the desiccantlayer is discharged out of the main body is opened within the upperchamber.

In the accumulator according to the present invention, the outlet portof the refrigerant suction tube is opened obliquely downward along aside surface of the main body.

In the accumulator according to the present invention, the refrigerantdischarge tube is bent in a substantially U-shape and has an outlet portopened outside of the upper chamber 13, and the refrigerant dischargetube includes an oil return hole through which oil accumulated togetherwith the refrigerant liquid is sucked, the oil return hole being formedin a bent part positioned in a bottom of the lower chamber.

In the accumulator according to the present invention, the desiccantlayer is filled with desiccant particles inside and fixed by perforatedmetals which are provided above and below the same and include aplurality of ventilation holes to bring the upper and lower chambers incommunication with each other and transfer only the refrigerant gas.

The accumulator according to the present invention further includes anoil separation layer which is provided in the lower chamber andseparates the refrigerant liquid from the oil for accumulation, in whichthe oil separation layer is composed of a fiber or porous material.

EFFECTS OF THE INVENTION

According to the aforementioned constitution, the outlet port of therefrigerant suction tube is opened within the lower chamber, and theinlet port of the refrigerant discharge tube is opened within the upperchamber which is separated from the lower chamber by the desiccantlayer. Accordingly, the refrigerant liquid sucked through therefrigerant suction tube is not directly sucked into the inlet port ofthe refrigerant discharge tube. Moreover, even if the refrigerant liquidruffles the inside of the lower chamber, the refrigerant liquid does notreach the inlet port of the refrigerant discharge tube. The refrigerantliquid is therefore not sucked into the compressor, and the damage ofthe compressor due to liquid or wet compression can be prevented.

Furthermore, the outlet port of the refrigerant suction tube is openedobliquely downward along the side surface of the main body. Accordingly,the refrigerant liquid and oil flown into the lower chamber aredischarged along the side surface of the main body and flows in acircular motion toward the center. At this time, the oil with a highspecific gravity is deposited in a lower part by centrifugation whilethe refrigerant liquid with a specific gravity lower than that of theoil is deposited in an upper part. Accordingly, the oil can be easilyseparated from the refrigerant liquid and can be surely returned to thecompressor.

Still furthermore, the oil return hole is formed in the bent partpositioned in the bottom of the lower chamber. Moreover, the refrigerantliquid and the oil sucked through the refrigerant suction tube into thelower chamber flow into the center of the lower chamber in a circularmotion, and the oil with a high specific gravity is deposited in lowerpart by centrifugation while the refrigerant liquid with a low specificgravity is deposited in upper part. Accordingly, the oil deposited inthe lower part of the lower chamber can be sucked through the oil returnhole.

Still furthermore, the desiccant layer is fixed by the perforated metalsprovided above and below the same. Accordingly, the desiccant layer canbe easily positioned while the gas ventilation between the upper andlower chambers is maintained.

Still furthermore, the oil separation layer is provided in the lowerchamber. Accordingly, the refrigerant liquid and oil can be easilyseparated, and the oil can be surely returned to the compressor. Inaddition, the liquid surface at the interface between the liquidrefrigerant and oil can be stabilized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of an accumulator accordingto a first embodiment.

FIG. 2 is a schematic cross-sectional view of an accumulator accordingto a second embodiment.

FIG. 3 is a schematic cross-sectional view of a conventional example ofa general accumulator.

EXPLANATION OF REFERENCE NUMERALS

-   10, 20, ACCUMULATOR-   11, TANK-   12, DESICCANT LAYER-   13, UPPER CHAMBER-   14, LOWER CHAMBER-   15 a, 15 b, 15 c, PERFORATED METAL-   16, 19, REFRIGERANT SUCTION TUBE-   16 a, 19 a, INLET PORT (REFRIGERANT SUCTION TUBE)-   16 b, 19 b, OUTLET PORT (REFRIGERANT SUCTION TUBE)-   17, REFRIGERANT/OIL DISCHARGE TUBE-   17 a, INLET PORT (REFRIGERANT/OIL DISCHARGE TUBE)-   17 b, OUTLET PORT (REFRIGERANT/OIL DISCHARGE TUBE)-   17 c, OIL RETURN HOLE-   18, OIL SEPARATION LAYER

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a description is given of embodiments of an accumulatoraccording to the invention. In the following description, a gas-liquidmixed refrigerant is properly abbreviated to a refrigerant.

First Embodiment

FIG. 1 is a schematic cross-sectional view of an accumulator accordingto a first embodiment. An accumulator 10 of this embodiment includes asubstantially cylindrical tank 11 as a main body and a desiccant layer12 above the middle of the main body. This desiccant layer 12 dividesthe inside of the main body into upper and lower spaces. The upper spaceis partitioned as an upper chamber 13 in which refrigerant gas flows,and the lower space is partitioned as a lower chamber 14 in whichrefrigerant liquid and oil are accumulated.

The desiccant layer 12 is filled with particles of a desiccant insideand has functions of gas-liquid separation and moisture adsorption. Thisdesiccant layer 12 is fixed at a predetermined position by perforatedmetals 15 a and 15 b arranged above and below the same. Each of theseperforated metals 15 a and 15 b is formed into a circle in a plan viewand includes a plurality of not-shown ventilation holes in the surface.The upper and lower chambers 13 and 14 communicate with each otherthrough the desiccant layer 12. The desiccant layer 12 sandwiched by theperforated metals 15 a and 15 b transmits only refrigerant gas.

In the tank 11, a refrigerant suction tube 16, through which thegas-liquid mixed refrigerant is sucked into the tank 11, is providedsubstantially vertically so as to penetrate the desiccant layer 12 andperforated metals 15 a and 15 b. An inlet port 16 a of the refrigerantsuction tube 16 is opened to the outside from the upper part of theupper chamber 13 and is coupled to a refrigerant pipe connected to anot-shown internal heat exchanger. An outlet port 16 b of therefrigerant suction tube 16 is opened in the lower chamber 14. Theoutlet port 16 b is opened obliquely downward along the side surface ofthe tank 11. Accordingly, refrigerant liquid and oil contained in therefrigerant discharged from the outlet port 16 b of the refrigerantsuction tube 16 are discharged along the side surface of the tank 11 toflow toward the center in a circular motion as shown by a thick dashedarrow.

The tank 11 includes a refrigerant/oil discharge tube 17, through whichthe refrigerant gas obtained by gas-liquid separation of the desiccantlayer 12 is discharged out of the tank 11. The refrigerant/oil dischargetube 17 is bent in a substantially U shape. An inlet port 17 a thereofis opened within the upper chamber 13, and an outlet port 17 b thereofis opened to the outside of the upper chamber 13 and coupled to arefrigerant pipe connected to a not-shown compressor. In the bent partof the refrigerant/oil discharge tube 17 positioned in the bottom of thelower chamber 14, an oil return hole 17 c is formed, through which oilaccumulated together with the refrigerant liquid is sucked.

In the accumulator 10 constituted as described above, the gas-liquidmixed refrigerant fed from the not-shown internal heat exchanger issucked from the not-shown refrigerant pipe through the refrigerantsuction tube 16 to the lower chamber 14. The refrigerant liquid and oilcontained in the sucked gas-liquid mixed refrigerant are dischargedalong the side surface of the tank 11 and flow toward the center in acircular motion to be accumulated in the lower chamber 14. Therefrigerant gas passes through the not-shown ventilation holes formed inthe perforated metal 15 b and the desiccant layer 12 and has moistureremoved here. The refrigerant gas further passes through the upperperforated metal 15 a and flows into the upper chamber 13.

The sucked gas-liquid mixed refrigerant is subjected to gas-liquidseparation, and the refrigerant liquid and oil are accumulated in thelower chamber 14 while the refrigerant gas is flown into the upperchamber 13. The refrigerant gas flown into the upper chamber 13 issucked from the inlet port 17 a of the refrigerant/oil discharge tube 17as shown by solid arrows and discharged to the refrigerant pipeconnected to the not-shown compressor together with the oil.

On the other hand, the refrigerant liquid and oil sucked from therefrigerant liquid suction tube 16 to the lower chamber 14 flow towardthe center of the lower chamber 14 in a circular motion. At this time,the oil with a high specific gravity is deposited in lower part (an areaA) by centrifugation while the refrigerant liquid with a low specificgravity is deposited in upper part (an area B). The oil deposited in thelower part of the lower chamber 14 is sucked through the oil return hole17 c of the refrigerant/oil discharge tube 17 and discharged to therefrigerant pipe connected to the not-shown compressor together with therefrigerant gas.

In the accumulator 10 of the aforementioned first embodiment, the outletport 16 b of the refrigerant suction tube 16 is opened within the lowerchamber 14, and the inlet port 17 a of the refrigerant/oil dischargetube 17 is opened within the upper chamber 13 with the desiccant layer12 interposed therebetween. Accordingly, the refrigerant liquid suckedthrough the refrigerant suction tube 16 is not directly sucked into theinlet port 17 a of the refrigerant/oil discharge tube 17. Moreover, evenif the refrigerant liquid flown into the chamber 13 ruffles the insideof the lower chamber 13, the refrigerant liquid does not reach the inletport 17 a of the refrigerant/oil discharge tube 17. Accordingly, therefrigerant liquid is not sucked into the compressor, and the damage ofthe compressor due to liquid and wet compression can be prevented.

In the first embodiment, moreover, the outlet port 16 b of therefrigerant suction tube 16 is opened obliquely downward along the sidesurface of the tank 11. Accordingly, the refrigerant liquid and oilflown into the lower chamber 14 are discharged along the side surface ofthe tank 11 and flown toward the center in a circular motion. At thistime, the oil with a high specific gravity is deposited in the lowerpart while the refrigerant liquid with a specific gravity lower thanthat of the oil is deposited in the upper part. Accordingly, even whenthe oil is compatible with the refrigerant of carbon dioxide, the oilcan be easily separated from the refrigerant liquid and can be surelyreturned to the compressor. The present invention thus has an effect onthe case of using oil compatible with carbon dioxide refrigerant.

Furthermore, the desiccant layer 12 is provided above the middle of themain body, so that it is allowed to make enough space in the lowerchamber 14 for the accumulated refrigerant liquid. Accordingly, it ispossible to accumulate redundant refrigerant due to variations in loadduring cooling operation in a sufficient space.

The refrigerant gas warmed during operation of the refrigerating systemis sucked by the accumulator 10, and the refrigerant liquid accumulatedin the lower chamber 14 is exposed to heat of the refrigerant gas to begasified. The gasified refrigerant passes through the desiccant layer 12and is discharged through the refrigerant/oil discharge tube 17.

Moreover, the desiccant layer 12 is fixed by the perforated metals 15 aand 15 b provided above and below the same. Accordingly, the desiccantlayer 12 can be easily positioned with ventilation maintained betweenthe upper and lower chambers 13 and 14.

Second Embodiment

FIG. 2 is a schematic cross-sectional view of an accumulator accordingto a second embodiment. The second embodiment is described below withparts equivalent to those of the first embodiment given the samenumerals.

The accumulator 20 of this embodiment includes an oil separation layer18 in order to separately store the refrigerant liquid and oil. The oilseparation layer 18 is supported in the substantially middle of thelower chamber 14 by a perforated metal 15 c. The oil separation layer 18is composed of a fiber material such as a felt material or a porousmaterial such as sponge and has a function of separating oil fromrefrigerant liquid. The refrigerant liquid thus passes through the oilseparation layer 18 (and the perforated metal 15 c) to be accumulated inupper part of the lower chamber 14, and the oil is separated by the oilseparation layer 18 and accumulated in lower part of the lower chamber14.

A refrigerant suction tube 19 is provided substantially vertically so asto penetrate the desiccant layer 12 and perforated metals 15 a and 15 b.The inlet port 19 a of the refrigerant suction tube 19 is opened to theoutside form the upper part of the upper chamber 13 and is coupled tothe refrigerant pipe connected to the not-shown internal heat exchanger.An outlet port 19 b thereof is opened within the lower chamber 14.

In the constitution of the second embodiment, the refrigerant liquidsucked through the refrigerant suction tube 19 is not directly suckedinto the inlet port 17 a of the refrigerant/oil discharge tube 17.Moreover, even if the refrigerant liquid flown into the lower chamber 14ruffles the inside of the lower chamber 14, the refrigerant liquid doesnot reach the inlet port 17 a of the refrigerant/oil discharge tube 17.Accordingly, the refrigerant liquid is not sucked into the compressor,and the damage of the compressor due to the liquid or wet compressioncan be prevented.

In the second embodiment, furthermore, the oil separation layer 18supported by the perforated metal 15 c is provided in the substantiallymiddle of the lower chamber 14. Even if the amount of refrigerant liquidand oil is too small to cause centrifugation unlike the firstembodiment, accordingly, the refrigerant and oil can be more easilyseparated, and the oil can be surely returned to the compressor. Inaddition, the liquid surface at the interface between the refrigerantliquid and oil can be stabilized.

Furthermore, in addition to the aforementioned effects, the part of theconstitution of the second embodiment similar to that of the firstembodiment can provide similar effects.

INDUSTRIAL APPLICABILITY

The present invention can be applied to not only refrigerating cycles ofair conditioners for vehicles but also refrigerating cycles of a widerange of air conditioners.

1-5. (canceled)
 6. An accumulator comprising: a main body; and adesiccant layer which is provided above a middle of the main body todivide the main body into upper and lower chambers; wherein a gas-liquidmixed refrigerant sucked into the lower chamber is subjected togas-liquid separation in the desiccant layer, only the refrigerant gasis transferred to the upper chamber, an outlet port of a refrigerantsuction tube through which the refrigerant is sucked into the body isopened within the lower chamber; and an inlet port of a refrigerantdischarge tube through which the refrigerant gas obtained by thegas-liquid separation in the desiccant layer is discharged out of themain body is opened within the upper chamber.
 7. The accumulatoraccording to claim 6, wherein the outlet port of the refrigerant suctiontube is opened obliquely downward along a side surface of the main body.8. The accumulator according to claim 6, wherein the refrigerantdischarge tube is bent in a substantially U-shape and has an outlet portopened outside of the upper chamber, and the refrigerant discharge tubeincludes an oil return hole through which oil accumulated together withthe refrigerant liquid is sucked, the oil return hole being formed in abent part positioned in a bottom of the lower chamber.
 9. Theaccumulator according to claim 6, wherein the desiccant layer is filledwith desiccant particles inside and fixed by perforated metals which areprovided above and below the same and include a plurality of ventilationholes to bring the upper and lower chambers in communication with eachother and transfer only the refrigerant gas.
 10. The accumulatoraccording to claim 6 further comprising: an oil separation layer whichis provided in the lower chamber and separates the refrigerant liquidfrom the oil for accumulation, wherein the oil separation layer iscomposed of a fiber or porous material.